Spring-driven motors



1966 K. A. E. MOORE ETAL 3,288,126

SPRING-DRIVEN MOTORS 2 Sheets-Sheet 1 Filed April 15, 1964 A 7702 NEU Nov. 29, 1966 K, A. E. MOORE ETAL 3,288,126

SPRING-DRIVEN MOTORS Filed April 13, 1964 2 Sheets-Sheet 2 Fig.3.

United States Patent 3,288,126 SPRING-DRIVEN MOTORS Kenneth Alfred Edgar Moore and Edward Aylett Moore,

both of West Timber, Bucklers Yard, Beau-lieu, Hampshire, England Filed Apr. 13, 1964, Ser. No. 359,047

Claims. (Cl. 123-479) The present invention relates to starters for internal combustion engines.

Internal combustion engines are commonly started by means of an electric motor and battery. For large engines, such as marine diesel engines for example, the electrical starting equipment is heavy and expensive and the mechanism by means of which the electric motor is engaged with and disengaged from the engine crankshaft is liable to wear. Batteries are liable to run down. Alternative forms of starter have been used, such as inertia starters, but these too are heavy and expensive.

The present invention has for its principal object to provide an internal combustion engine starter which is efiicient and yet relatively light and inexpensive.

According to the present invention there is provided a starter for an internal combustion engine comprising resilient means surrounding the engine shaft or a shaft coaxial with the engine shaft, fixed at one end relatively to the engine frame and having its opposite end coupled or capable of being coupled to the engine shaft, and means for displacing said opposite end to store energy in the resilient means, the arrangement being such that upon release of said opposite end the stored energy is released and serves to rotate the engine shaft.

There is preferably provided between said opposite end of the resilient means and the engine shaft an over-running clutch which permits the displacement of the said opposite end during energy storage without effecting rotation of the engine shaft. In order that there shall be no shock when the said opposite end is released and coupled to the engine shaft, it has been found important to use as over-running clutch one in which the driving member locks to the driven member, in the driving direction, in any position and substantially without back-lash (as distinct from, for example, a ratchet and pawl free-wheel which operates in finite steps). Thus the clutch is preferably of a type comprising a coupling member which, in the free-wheeling direction, is located with very small clearance between the driving and driven members but which, in the driving direction, is arranged to wedge between the driving and driven members.

The invention will be described by way of example with reference to the accompanying drawings in which:

FIG. 1 is a view in sectional elevation on the line II of FIG. 2 of one installation according to the invention,

FIG. 2 is a partly sectional plan view of the installation,

FIG. 3 is a plan view, partly in section, of another embodiment of the invention, and

FIG. 4 is a diagrammatic view of a part of a preferred form of over-running clutch for use in the present invention.

Referring to FIGS. 1 and 2, an engine crankshaft is coupled to a drum 11 through an over-running clutch 12. It is important, as already stated, that the clutch 12 should be one having only small back-lash and a suitable device is a Sprag clutch marketed by Renold Chains Limited. The principle of operation of this clutch is shown in the diagrammatic sectional view of part of the clutch, see FIG. 4. It comprises an outer member 50 having an inner cylindrical surface 51, an inner member 52 having an outer cylindrical surface 53 coaxial with the surface 51 and a number of sprag or wedging coupling members 54 located between the surfaces 51 and 53 and so shaped,

particularly by making the dimension A-A greater than BB, that in one direction of rotation the sprag members tilt and wedge between the surfaces 51 and 53. The sprag members transmit torque in this direction of rotation. In the opposite direction of rotation the sprag members bear only lightly against the two surfaces 51 and 53. Usually the sprag members abut one another and are held in light contact continuously with the surfaces 51 and 53 by means of an expanding coil spring 55.

Within the drum 11 is a steel spiral spring 13 having its inner end fixed to a member 14 which is fixed relatively to the engine bed 15. The outer end of the spring 13 is fixed to the drum 11.

Fixed to the outside of the drum 11 is a ring gear 16. A pinion 17 is fixed to a shaft 18 which also has fixed thereto a crank-handle 19. The shaft 18 is rotatably mounted on a lever arm 20 hinged to a member fixed relatively to the engine bed at 21. The lever arm 20 is normally held against a stop 22 by means of a light spring 23 but can be moved inward to cause the pinion 17 to engage the ring gear 16. In this inner position the lever arm 20 can be held by a latch 24 which is pivoted about an axis fixed relatively to the engine bed. A backstop or free-wheel device 25 has its inner member fixed to the shaft 18 and its outer member fixed by an extension piece 26 to the lever arm 20. The back-stop 25 permits rotationof the shaft 18 relatively to the lever arm 20 in only one direction, namely a clockwise direction in FIG. 1. r 7

In order to start the engine, the crank-handle 19 is turned clockwise (in FIG. 1) and thus the ring gear 16 and drum 11 are turned anti-clockwise. Since the inner end of the spiral spring 13 is fixed, rotation of the drum 11 stores energy in the spring 13, the back-stop 25 preventing counter rotation of the crank-handle 19. When the spring 13 has been fully wound, the latch 24 is moved clockwise in FIG. 1 to release the lever arm 20 which flies outwards under the action of the spring 23, thus disengaging the pinion 17 from the ring gear 16. The ring gear 16 and drum 11 then fly back (in a clockwise direction in FIG. 1) and through the over-running clutch 12 apply an impulsive torque in a clockwise direction to the crankshaft 10 Owing to the absence of any gearing between the drum 11 and the crankshaft the arrangement described can be inexpensive and robust.

If desired the outer end of the spiral spring may be anchored to the engine bed and the inner end fixed to the drum. In this case the drum may be located inside the spring and the ring gear 16 displaced axially from the drum sufliciently to clear the pinion 17 or an internal ring gear could be used.

In FIG. 3 parts which are the same as those in FIG. 2 are given the same references and need not be described. In this example the ring gear 16 is fixed to the upper end of a stack of resilient cylinders 41. The cylinders 41 may for instance, be of rubber and their upper and lower surfaces are fixed by means of a suitable strong adhesive to metal washers 42. The stack is located in position by means of a rod 43 passing through its centre. The bottom of the stack is fixed to a member 44 which is fixed upon the engine bed 27.

This embodiment operates similarly to that already described excepting that the energy required for starting is stored by torsion of the resilient cylinders 41.

The rubber cylinders 41 may be tapered in such a Way that their radius increases with their axial length in such a manner that the shear stress is substantially the same at allradii.

The arrangement, according to the present invention, in which one end of the resilient member in which starting energy is stored is fixed relatively to the engine bed, the opposite end being moved in one direction in order to store energy and moving in the opposite direction to release energy for starting, results in great simplicity of construction.

We claim:

1. A starter for an internal combustion engine having an engine frame normally fixedly supported, in use, and a shaft by which drive is transmitted by said engine, said starter comprising resilient means surrounding said shaft, one end of said resilient means being fixed relatively to said frame clutch means for coupling the other end of said resilient means to said shaft in one direction of rotation of said shaft, means for displacing said other end of said resilient means around said shaft to store energy in said resilient means and means for locking said other end of said resilient means in the displaced position, said resilient means serving, when said locking means are unlocked, to release the stored energy and rotate said shaft in a direction opposite to that of said displacement, and said clutch means being a sprag clutch having negligible back-lash and including a first member drivably connected to said other end of the resilient means, a second member drivably connected to said engine shaft, said first and second members having facing coaxial circular cylindrical surfaces bounding an annular space, a plurality of coupling members disposed in said annular space, said coupling members having a shape other than circular in planes perpendicular to the axis of said clutch, and spring means biasing said coupling members into continuous engagement with said circular cylindrical surfaces, said coupling members wedging between said cylindrical surfaces in said one direction of rotation of said other end of said resilient means and sliding freely over said cylindrical surfaces in the opposite direction of rotation of said other end.

2. A starter according to claim 1, wherein said resilient means comprises a spiral spring.

3. A starter according to claim 1 comprising a toothed wheel mounted for rotation about the axis of said shaft, said other end of the resilient means being fixed to said toothed wheel, a pinion engageable with said toothed wheel, a back-stop for said pinion limiting rotation of said pinion to one direction and crank means for rotating said pinion and thereby rotating said toothed wheel.

4. A starter according to claim 3, comprising a lever having said pinion rotatably mounted thereon, said lever being rockably mounted to bring said pinion into and out of engagement with said toothed wheel and said locking means engaging said lever to hold said pinion in mesh with said toothed wheel.

5. A starter for an internal combustion engine having an engine frame normally fixedly supported, in use, and a shaft by which drive is transmitted by said engine, said starter comprising resilient means surrounding said shaft, one end of said resilient means being fixed relatively to said frame, an over-running clutch coupling the other end of said resilient means to said shaft in one direction of rotation of said shaft, said clutch comprising two coaxial members mounted one within the other and having facing circular cylindrical surfaces bounding an annular space between them, one of said members being fixed relatively to said shaft and the other of said members being fixed relatively to said other end of the resilient means, a plurality of wedging members disposed in said annular space, said wedging members being of other than circular shape in planes perpendicular to the axis of said clutch and having wedging engagement with said circuilar surfaces of said coaxial members and preventing relative rotation between said coaxial members in said one direction of rotation of said shaft and permitting free relative rotation between said coaxial members in the opposite direction of rotation, spring means biasing said wedging members into continuous engagement with the circular surfaces of said coaxial members, means for rotating said other end of said resilient means in said opposite direction to store energy in said resilient means, and releasable means for locking said other end of said resilient means in the energy-storing position.

References Cited by the Examiner UNITED STATES PATENTS 1,064,132 6/1913 Curtis 123--179 2,413,045 12/1946 Hoekstra 39 2,631,706 3/1953 Dodge 19245.1 2,773,563 12/1956 Bevis et al. 18539 2,845,801 8/1958 Bridges 18539 X MARK NEWMAN, Primary Examiner.

KARL J. ALBRECHT, RICHARD B. WILKINSON,

DONLEY .T. STOCKING, Examiners.

L. M. GOODRIDGE, Assistant Examiner. 

1. A STARTER FOR AN INTERNAL COMBUSTION ENGINE HAVING AN ENGINE FRAME NORMALLY FIXEDLY SUPPORTED, IN USE, AND A SHAFT BY WHICH DRIVE IS TRANSMITTED BY SAID ENGINE, SAID STARTER COMPRISING RESILIENT MEANS SURROUNDING SAID SHAFT, ONE END OF SAID RESILIENT MEANS BEING FIXED RELATIVELY TO SAID FRAME, CLUTCH MEANS FOR COUPLING THE OTHER END OF SAID RESILIENT MEANS TO SAID SHAFT IN ONE DIRECTION OF ROTATIONOF SAID SHAFT, MEANS FOR DISPLACNING SAID OTHER END OF SAID RESILIENT MEANS AROUND SAID SHAFT TO STORE ENERGY IN SAID RESILIENT MEANS AND MEANS FOR LOCKING SAID OTHER END OF SAID RESILIENT MEANS IN THE DISPLACED POSITION, SAID RESILIENT MEANS SERVING, WHEN SAID LOCKING MEANS ARE UNLOCKED, TO RELEASE THE STORED ENERGY AND ROTATE SAID SHAFT IN A DIRECTION OPPOSITE TO THAT OF SAID DISPLACEMENT, AND SAID CLUTCH MEANS BEING A SPRAG CLUTCH HAVING NEGLIGIBLE BACK-LASH AND INCLUDING A FIRST MEMBER DRIVABLY CONNECTED TO SAID OTHER END OF THE RESILIENT MEANS, A SECOND MEMBER DRIVABLY CONNECTED TO SAID ENGINE SHAFT, SAID FIRST AND SECOND MEMBERS HAVING FACING COAXIAL CIRCULAR CYLINDRICAL SURFACES BOUNDING AN ANNULAR SPACE, A PLURALITY OF COUPLING MEMBERS DISPOSED IN SAID ANNULAR SPACE, SAID COUPLING MEMBERS HAVING A SHAPE OTHER THAN CIRCULAR IN PLANES PERPENDICULAR TO THE AXIS OF SAID CLUTCH, AND SPRING MEANS BIASING SAID COUPLING MEMBERS INTO CONTINUOUS ENGAGEMENT WITH SAID CIRCULAR CYLINDRICAL SURFACES, SAID COUPLING MEMBERS WEDGING BETWEEN SAID CYLINDRICAL SURFACES IN SAID ONE DIRECTION OF ROTATION OF SAID OTHER END OF SAID RESILIENT MEANS AND SLIDING FREELY OVER SAID CYLINDRICAL SURFACES IN THE OPPOSITE DIRECTION OF ROTATION OF SAID OTHER END. 